TL;DR: These are all not good interview words, but not because of the contraction (which chasly points out is more likely native speakers softly saying syllables or eliding them); but because the words are not active, strong words. Using active words helps you make your case for being hired.
Breaking down case by case:
For "wanna", on a similar note to chasly's answer, it's likely that 'want to' is nearly never said exactly as such by a native speaker. This isn't "wanna" though, or even with the schwa, necessarily; what I find when I record myself saying "want to" is "wanto" - eliding the second 't'. Other accents may be more similar to chasly's; I'm not sure. I definitely pronounce the 't' once, and most people I am around do the same, but that's upper midwestern US and might be very different in the northeast, south, not to mention UK or Australia. This is the only one of these I'd expect to use in an interview, because "want to" is a reasonably active phrase ("q: How long do you plan to stay at the company? a: I want to stay at least five years").
"Gotta" is clearly informal, as is "got"; it would similarly be pronounced with the elided second t were it to be said, but avoid 'got' entirely in the common usage ("I've got to ...") as it's really better said as "I need to". It's not that slang-y, and is probably effectively "common usage" now rather than slang, but some interviewers might see it as slang, and the word just isn't needed. Use active language here instead.
"Gonna" is informal and passive. "Going to" is again better to avoid, as it's more passive; "I'm going to go to the store" is less effective of a tense than "I will go to the store" (if you need to convey future) or "I am going to the store" (for present tense). If you were to say "going to", though, "going to" is pretty normal to say in full I think.
"Kinda" I'd also avoid, just as I'd avoid "kind of". Again, this is more a matter of being active and direct: "kind of" implies weakness, that you're unsure. (Unless you mean "Chocolate is a kind of candy", which is fine, but definitely not used as "kinda" there.) "q: Do you know SQL? a: Kind of" isn't something you should be saying in an interview; use more definite language.
"Lotta" again is one to avoid; while as with chasly's answer it's not really a true contraction so much as a natural way of saying "lot of" with very little emphasis on "f" and the "o" turning into a schwa, I'd avoid "lot of" where possible, because it's usually taking the place of a more accurate or direct answer - "q: How much experience do you have with SQL? a: I have a lot of experience" is not a good answer, it should be "a: I have ten years' experience".